Heat exchanger

ABSTRACT

A heat exchanger has a tank and a core including a plurality of tubes stacked in a longitudinal direction of the tank and in communication with the tank. The heat exchanger further has an inlet port for introducing a fluid into the tank and a first projection on an inner wall of the tank at a position where the fluid flowing from the inlet port hits on. The first projection is configured to change a flow direction of the fluid flowing from the inlet port in the longitudinal direction of the tank. For example, the first projection projects from the inner wall of the tank toward the inlet port in a form of substantially wedge.

CROSS REFERENCE TO RELATED APPLICATION

This application is based on Japanese Patent Application No. 2006-37203 filed on Feb. 14, 2006, the disclosure of which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a heat exchanger.

BACKGROUND OF THE INVENTION

A heat exchanger generally has a core constructed of a stack of tubes and a tank. For example, ends of the tubes are connected to a core plate, which is fixed to the tank, so as to make communication with the tank. Also, the tank is provided with an inlet pipe defining an inlet port for introducing an internal fluid into the heat exchanger. The inlet pipe is for example substantially perpendicular to a longitudinal direction of the tank. Such a heat exchanger is for example used as a radiator for cooling an engine cooling water.

In the heat exchanger, the internal fluid flowing from the inlet pipe collides with an inner wall of the tank, and then flows in the longitudinal direction of the tank. Therefore, resistance of the internal fluid to flow is likely to increase due to the collision with the inner wall.

Also, the internal fluid easily flows in the tubes that are located close to the inlet pipe, and is difficult to flow into the tubes that are located further from the inlet pipe. Therefore, flow speed distribution will be generated among the tubes. As a result, the core has a temperature distribution, causing deterioration of heat radiation efficiency and deterioration of durability due to thermal stress.

In a case that the heat exchanger is used as the radiator, a space for mounting the radiator in an engine compartment is generally limited. Despite such a condition, it is required to increase a size of the core so as to improve a heat exchanging performance. Therefore, it is proposed to reduce a size (height H1) of the tank, as shown in FIGS. 10A to 10C.

In this example, however, an inlet pipe 111 partly projects from a tank 110 by a dimension of H2 in a direction perpendicular to a longitudinal direction of the tank 110 with the size reduction of the tank 110. In this case, the amount of the internal fluid introduced into the tubes will be reduced with a distance from the inlet pipe 111. Thus, the flow speed distribution will be easily generated.

SUMMARY OF THE INVENTION

The present invention is made in view of the foregoing matter, and it is an object of the present invention to provide a heat exchanger capable of reducing resistance of a fluid to flow. Also, it is another object of the present invention to provide a heat exchanger capable of reducing flow speed distribution of the fluid.

According to an aspect of the present invention, a heat exchanger has a tank defining a tank space, a core including a plurality of tubes, an inlet port disposed to the tank for introducing a fluid into the tank space, and a first projection disposed on an inner wall of the tank at a position where the fluid flowing from the inlet port hits on. The tubes are stacked in a longitudinal direction of the tank and in communication with the tank space. Further, the first projection is configured to change a flow direction of the fluid in the longitudinal direction of the tank.

In this structure, a flow direction of the fluid flowing from the inlet port is changed in the longitudinal direction of the tank by the first projection. Therefore, resistance of the fluid when hitting on the inner wall of the tank, i.e., resistance of the fluid when entering the tank space, is reduced by the first projection.

Further, the fluid is effectively introduced toward longitudinal ends of the tank by the first projection. As such, flow speed distribution of the fluid among the tubes reduces. Accordingly, the flow of the fluid improves in the heat exchanger.

For example, the first projection has a wedge shape projecting from the inner wall of the tank toward the inlet port. Thus, the fluid flowing from the inlet port is divided in the longitudinal direction of the tank by an end of the first projection and further guided along side walls of the first projection, the side walls extending from the end. Alternatively, the first projection projects from the inner wall of the tank toward the inlet port and has a substantially triangular shape when viewed in a direction perpendicular to the longitudinal direction of the tank. The fluid flowing from the inlet port is divided in the longitudinal direction of the tank by an end of the triangular-shaped projection and further guided along side walls of the first projection.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings, in which like parts are designated by like reference numbers and in which:

FIG. 1 is a schematic front view of a heat exchanger according to a first embodiment of the present invention;

FIG. 2 is a partial perspective view of a coupling portion of a core and a tank of the heat exchanger according to the first embodiment;

FIG. 3A is a perspective plan view of the tank at a part adjacent to an inlet pipe according to the first embodiment;

FIG. 3B is a front view of the tank at the part adjacent to the inlet pipe according to the first embodiment;

FIG. 3C is a schematic bottom view of the tank at the part adjacent to the inlet pipe according to the first embodiment;

FIG. 4 is a cross-sectional view of the tank taken along a line IV-IV in FIG. 3B;

FIG. 5A is a schematic side view of a tank of a heat exchanger at a part adjacent to an inlet pipe according to a second embodiment of the present invention;

FIG. 5B is a schematic plan view of the tank at the part adjacent to the inlet pipe according to the second embodiment;

FIG. 5C is a schematic back view of the tank at the part adjacent to the inlet pipe according to the second embodiment;

FIG. 6A is a schematic side view of a tank of a heat exchanger at a part adjacent to an inlet pipe according to a third embodiment of the present invention;

FIG. 6B is a schematic plan view of the tank at the part adjacent to the inlet pipe according to the third embodiment;

FIG. 6C is a schematic back view of the tank at the part adjacent to the inlet pipe according to the third embodiment;

FIG. 7A is a schematic side view of a tank of a heat exchanger at a part adjacent to an inlet pipe according to a fourth embodiment of the present invention;

FIG. 7B is a schematic plan view of the tank at the part adjacent to the inlet pipe according to the fourth embodiment;

FIG. 7C is a schematic back view of the tank at the part adjacent to the inlet pipe according to the fourth embodiment;

FIG. 8A is a schematic side view of a tank of a heat exchanger at a part adjacent to an inlet pipe according to a fifth embodiment of the present invention;

FIG. 8B is a front view of a tank at the part adjacent to the inlet pipe for showing an example of a second projection according to the fifth embodiment of the present invention;

FIG. 8C is a front view of a tank at the part adjacent to the inlet pipe for showing another example of the second projection according to the fifth embodiment of the present invention;

FIG. 9 is a front view of a part of a heat exchanger according to a sixth embodiment of the present invention;

FIG. 10A is a perspective view of an inlet pipe of a tank of a heat exchanger of a related art;

FIG. 10B is a front view of the tank at a part adjacent to the inlet pipe of the related art; and

FIG. 10C is a side view of the tank of the related art.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS First Embodiment

A first embodiment will now be described with reference to FIGS. 1 to 4. As shown in FIG. 1, a heat exchanger is for example used as a radiator 100 that is generally arranged at a front part of an engine compartment of a vehicle for cooling an engine. For example, an engine cooling water flows in the radiator 100 as an internal fluid.

The radiator 100 has a core 130 including tubes 132, an upper tank 110 and a lower tank 120. The radiator 100 is for example a down-flow type heat exchanger and configured such that the cooling water flows the tubes 132 in a downward direction from the upper tank 110 toward the lower tank 120.

The core 130 provides a heat exchanging part for cooling the cooling water. The core 130 includes the tubes 132, fins 131, side plates 133 and core plates 140. For example, the fins 131 are corrugated fins having louvers in the form of slits. Each of the tubes 132 is constructed by joining a pair of plate members each having a substantially U-shaped cross-section. The plate members are for example welded at ends thereof, thereby to provide a passage space of the tube 132.

Each side plate 133 have a substantially U-shaped cross-section. The tubes 132 and the fins 131 are alternately stacked in a left and right direction in FIG. 1. The side plates 133 are disposed to a leftmost fin 131 and a rightmost fin 131 as reinforcement members for reinforcing the core 130.

The core plates 140 are disposed at upper and lower ends of the tubes 132. The core plates 140 extend in a direction parallel to a direction in which the tubes 132 and the fins 131 are stacked (hereafter, referred to as a stacking direction). Each core plate 140 is for example formed by drawing from a plate member. The core plate 140 is formed with tube insertion holes 142 at positions corresponding to the ends of the tubes 132. The ends of the tubes 132 are inserted to the tube insertion holes 142.

The preceding members constructing the core 130 are for example made of aluminum alloy having strength properties and resistance to corrosion. Those members are integrally brazed.

The upper tank 110 and the lower tank 120 are mechanically coupled to the upper and lower core plates 140 such as by crimping. The upper tank 110 and the lower tank 120 are for example made of resin such as polyamide resin.

The upper tank 110 is integrally formed with an inlet pipe 111 providing an inlet port for introducing the cooling water in the radiator 100. The lower tank 120 is integrally formed with an outlet pipe 112 providing an outlet port for discharging the cooling water from the radiator 100. The inlet pipe 111 and the outlet pipe 121 are formed on side walls of the upper tank 110 and the lower tank 120, respectively. The inlet pipe 111 and the outlet pipe 112 are in communication with an engine cooling water circuit through tubes such as rubber hoses.

As shown in FIG. 2, the upper tank 110 has a container-like shape having -an opening on one side. The upper tank 110 has a substantially U-shaped cross-section. The upper tank 110 is coupled to the upper core plate 140 so that the opening is covered by the upper core plate 140.

For example, the upper tank 110 has projections projecting outward on a perimeter of the opening. The projections provide stepped wall 112. On the other hand, the upper core plate 140 has a main wall 141 and coupling grooves 143 along ends of the main wall 141. The projections of the upper tank 110 is received in the coupling grooves 143 of the upper core plate 140 through sealing members 150. Further, ends 144 of the core plate 140 is folded over the stepped wall 112 of the upper tank 110. As such, the upper tank 110 and the upper core plate 140 are fixed to each other, thereby providing a tank space between them.

The tube insertion holes 142 are formed on the main wall 141 of the upper core plate 140. The upper ends of the tubes 132 are inserted in the tube insertion holes 142 of the upper core plate 140. Thus, the tubes 132 are in communication with the tank space of the upper tank 110.

Also, the main wall 141 of the upper core plate 140 is a base wall of the upper core plate 140, and an inner surface 141 a of the main wall 141 provides a bottom wall of the tank space. The coupling grooves 143 project more to outside of the tank than the main wall 141 so that inner bottom walls 143 a of the coupling grooves 143 are located closer to a center of the core 130 than an outer surface of the main wall 141. When the ends 144 of the upper core plate 140 are folded over the stepped walls 112 of the upper tank 110, the inner bottom walls 143 are pressed against the projections of the upper tank 110 through the sealing members 150.

The lower tank 120, the lower core plate 140 and the lower ends of the tubes 132 are coupled in the similar manner to the upper tank 110, the upper core plate 140 and the upper ends of the tubes 132.

Next, a structure of the upper tank 110 and the inlet pipe 111 will be described in detail with reference to FIGS. 3A to 4.

The inlet pipe 111, which has a pipe shape, is integrally formed with the upper tank 110. For example, the inlet pipe 111 is located at a substantially middle position in the longitudinal direction of the upper tank 110. Also, the inlet pipe 111 is formed such that the cooling water flows in the upper tank 110 in a direction substantially perpendicular to a longitudinal direction of the upper tank 110. That is, the inlet pipe 111 is disposed such that its axis is substantially perpendicular to the longitudinal direction of the upper tank 110. Also, an upper portion of the inlet pipe 111 is located higher than a top end of the upper tank 110, as shown in FIG. 3B.

The cooling water flowing from the inlet pipe 111 hits on an inner wall of the upper tank 110 and separates in the longitudinal direction, i.e., in the right and left direction in FIGS. 3A to 3C. In the embodiment, as shown in FIGS. 3C and 4, an inclined portion 116 and a first projection 115 are formed in the upper tank 110 at a position where the cooling water flowing from the inlet pipe 111 hits on. Namely, the inclined portion 116 and the first projection 115 are formed in the upper tank 110 directly downstream of a downstream end of the inlet pipe 111 with respect to a flow of the cooling water. The first projection 115 is located under the inclined portion 116.

As shown in FIG. 4, the inclined portion 116 extends from an upper portion of the downstream end of the inlet pipe 111 toward an end (projection end) 115 a of the first projection 115. The inclined portion 116 is inclined relative to the axis of the inlet pipe 111. The inclined portion 116 serves as a guide (guide vane) for directing the cooling water from the inlet pipe 111 to smoothly flow toward the first projection 115.

The first projection 115 is configured to change a flow direction of the cooling water in the longitudinal direction of the upper tank 110 such that the cooling water smoothly flows toward longitudinal ends of the upper tank 110. Specifically, the first projection 115 projects toward the inlet port defined by the inlet pipe 111 in a form of substantially wedge or V-shape. Thus, the first projection 115 includes the end 115 a and inclined side walls 115 b that converge with each other at the end 115 a. The side walls 115 b connect to the inner wall of the upper tank 110.

For example, as shown FIGS. 3A and 3C, the first projection 115 is formed such that the end 115 a is aligned with the axis of the inlet pipe 111. The side walls 115 b are inclined relative to the longitudinal direction of the upper tank 110. Thus, the amount of projection of the first projection 115 relative to an inner wall of the upper tank 110 is the maximum at the position corresponding to the end 115 a and gradually decreases in the longitudinal direction of the upper tank 110 due to the inclined side walls 115 b.

In this structure, the cooling water flowing from the inlet pipe 111 (arrow F1) is guided toward the first projection 115 along the inclined portion 116, and then divided into a rightward flow and a leftward flow (arrows F2, F3) by the end 115 a. The divided flows are further directed toward the right end and the left end of the upper tank 110 along the inclined side walls 115 b as guide walls (guide vanes).

Since the inclined portion 116 is formed between the downstream end of the inlet pipe 111 and the first projection 115, the cooling water smoothly flows toward the first projection 115 along the inclined portion 116. Thus, flow resistance of the cooling water at an inlet of the upper tank 110 reduces.

Further, the flow of the cooling water is divided and changed in the longitudinal direction of the upper tank 110 by the first projection 115. Thus, flow resistance of the cooling water at an inlet of the upper tank 110 further reduces.

Accordingly, even if the inlet pipe 111 partly projects from the top end of the upper tank 110 due to size reduction of the upper tank 110, the resistance of the cooling water to flow into the upper tank 110 reduces. In other words, since the resistance of the cooling water when entering the upper tank 110 is reduced by the first projection 115 and the inclined portion 116, a size of the upper tank 110 can be reduced.

The shape of the first projection 115 is not limited to the substantially wedge shape as long as it includes the end 115 a for changing the flow direction of the cooling water and the inclined side walls 115 b as the guide vanes.

Second Embodiment

A second embodiment will be described with reference to FIGS. 5A to 5C. In the second embodiment, the downstream end of the inlet pipe 111 is connected to the upper tank 110 through a round or curved wall (R-shaped wall), instead of the inclined portion 116 of the first embodiment. The first projection 115 is formed over the portion to which the cooling water flowing from the inlet pipe 111 hits on. Namely, the first projection 115 is formed from the upper portion of the downstream end of the inlet pipe 111 and over the curved wall.

Also in the second embodiment, the first projection 115 has the wedge or V-shape, and includes the end 115 a and the inclined side walls 115 b (guide vanes). In a case that the inlet pipe 111 is formed at the substantially middle position of the upper tank 110 in the longitudinal direction, the end 115 a is aligned with the axis of the inlet pipe 111, as shown in FIG. 5A. The inclined side walls 115 b extend from the end 115 a and connect to the inner wall of the upper tank 110. Thus, the amount of projection of the first projection 115 is the maximum at the position corresponding to the axis of the inlet pipe 111 and gradually reduces in the right and left direction.

Also in the second embodiment, it is configured such that the cooling water flowing from the inlet pipe 111 hits on the first projection 115. The cooling water is divided into the leftward flow and the rightward flow by the end 115 a of the first projection 115 and directed toward the right and left ends of the upper tank 110 along the inclined side walls 115 b. Thus, the flow direction of the cooling water is smoothly changed by the first projection 115.

Accordingly, since the cooling water smoothly flows into the upper tank 110 along the first projection 115, the resistance of the cooling water when entering the upper tank 110 reduces. Thus, the size of the upper tank 110 is reduced. Further, since the downstream end of the inlet pipe 111 connects to the upper tank 110 through the curved wall, i.e., the upstream portion of the first projection 115 is curved, the cooling water further smoothly flows into the upper tank 110.

Third Embodiment

A third embodiment will be described with reference to FIGS. 6A to 6C. In the third embodiment, the first projection 115 is formed at the position where the cooling water flowing from the inlet pipe 111 hits on, but has a shape different from that of the first and second embodiments.

For example, the first projection 115 projects from the inner wall of the upper tank 110 toward the inlet pipe 111, and has a substantially triangular shape when viewed along the axis of the inlet pipe 111, as shown in FIG. 6C. Further, the first projection 115 is formed such that the end (apex of the triangular) 115 a is located on the axis of the inlet pipe 111 and the first and second sides 115 b extend from the end 115 a diagonally downward relative to the longitudinal direction of the upper tank 110. Further, a bottom side 115 c, which is on a side opposite to the end 115 a, is located higher than the opening of the upper tank 110, i.e., the main wall 141 of the core plate 140.

Similar to the above embodiments, the cooling water flowing from the inlet pipe 111 is divided by the end 115 a of the first projection 115 and directed in the longitudinal direction of the upper tank 110 by the sides 115 b. Therefore, the flow resistance of the cooling water when flowing into the upper tank 110 reduces. Also, the downstream end of the inlet pipe 111 is curved toward the end 115 a of the first projection 115, the cooling water smoothly flows toward the first projection 115.

In general, the flow speed of the cooling water reduces with the distance from the inlet pipe 111. This results in flow speed distribution of the cooling water among the tubes 132. Considering this matter, in the third embodiment, a flow of the cooling water in a downward direction is reduced by the first projection 115 having the substantially triangular shape.

In other words, the cooling water flowing from the inlet pipe 111 is divided into the rightward flow and the leftward flow by the end 115 a and directed by the sides 115 b. Therefore, the amount of the cooling water flowing into the tubes 132 located under or adjacent to the inlet pipe 111 are reduced by the first projection 115. As a result, the cooling water more easily reaches the longitudinal ends of the upper tank 110. As such, the flow speed distribution of the cooling water in the core 130 reduces. Accordingly, the flow of the cooling water in the radiator 100 improves.

Also in this embodiment, the cooling water flowing from the inlet pipe 111 is smoothly directed toward the rightward flow and the left ward flow by the first projection 115. Therefore, the resistance of the cooling water to flow into the upper tank 110 reduces, and the size of the upper tank 110 reduces.

Fourth Embodiment

A fourth embodiment will be described with reference to FIGS. 7A to 7C. In the fourth embodiment, the first projection 115 has a substantially triangular shape, similar to the third embodiment. However, the bottom side of the first projection 115 is elongated in the longitudinal direction of the upper tank 110, as compared with the third embodiment.

As shown in FIG. 7C, the first projection 115 has the end 115 a similar to the third embodiment. Also, the first projection 115 has the sides 115 b extending from the end 115 a. Further, the lower ends of the sides 115 b connect to a longitudinal portion providing a bottom side 115 d. The bottom side 115 d is longer than the bottom side 115 c of the third embodiment in the longitudinal direction of the upper tank 110.

The cooling water flowing from the inlet pipe 111 is divided by the end 115 a and directed in the longitudinal direction of the upper tank 110 along the sides 115 b. Here, the longitudinal portion serves as a guide (guide vane) for further directing the divided flows of the cooling water toward the longitudinal ends of the upper tank 110.

In this construction, the amount of the cooling water flowing into the tubes 132 that are located adjacent to the inlet pipe 111 is reduced by the longitudinal portion of the first projection 115. That is, the cooling water is further introduced toward the longitudinal ends of the upper tank 110 and effectively distributed into the tubes 132 that are further from the inlet pipe 111. Accordingly, the flow speed distribution of the cooling water further improves in the core 130, and the flow of the cooling water in the radiator 100 improves. This structure may be effective when the upper tank 110 is very long.

Fifth Embodiment

A fifth embodiment will be described with reference to FIGS. 8A to 8C. Here, the upper tank 110 is configured such that the downward flow of the cooling water toward the tubes 132 adjacent to the inlet pipe 111 is reduced and the cooling water is further effectively directed toward the first projection 115.

As shown in FIG. 8A, the first projection 115 is formed at the position where the cooling water flowing from the inlet pipe 111 hits on. The first projection 115 has a substantially wedge shape projecting toward the opening of the inlet pipe 111, similar to the second embodiment.

Further, a second projection 117 is formed on a lower inner wall of the downstream end of the inlet pipe 111. The second projection 117 gradually projects toward its downstream end. Namely, the amount of projection of the second projection 117 gradually increases toward the downstream end, as shown in FIG. 8A. The second projection 117 is configured as a guide for introducing the cooling water toward a relatively upper inner wall of the upper tank 110.

For example, the second projection 117 has an inclined surface, as shown in FIG. 8B. A downstream end of the inclined surface is higher than an upstream end of the inclined surface.

Alternatively, the second projection 117 can have a substantially wedge shape or a reversed V-shape, as shown in FIG. 8C. In the example of FIG. 8C, the second projection 117 has an end and sloped walls extending from the end and sloping in the longitudinal direction of the upper tank 110. Thus, the second projection 117 shown in FIG. 8C changes the flow direction of the cooling water in the longitudinal direction of the upper tank 110, similar to the first projection 115.

In this construction, the cooling water is easily directed toward a portion above the first projection 115 by the second projection 117. Further, the flow of the cooling water is divided in the rightward and leftward flows by the first projection 115. Therefore, the flow of the cooling water toward the tubes 132 that are adjacent to the inlet pipe 111 is reduced by the second projection 117.

Further, since the cooling water is directed above the first projection 115 by the second projection 117, the flow of the cooling water is effectively divided by the first projection 115 and directed in the longitudinal direction of the upper tank 110. Namely, since the amount of the cooling water flowing into the tubes 132 adjacent to the inlet pipe 111 reduces, the amount of the cooling water introduced toward the longitudinal ends of the upper tank 110 increases. As such, the cooling water more easily reaches the longitudinal ends of the upper tank 110.

Accordingly, the flow speed distribution of the cooling water improves. In other words, the cooling water is substantially equally introduced into the tubes 132. Moreover, the flow resistance of the cooling water to flow toward the first projection 115 is reduced by the second projection 117.

In the example shown in FIG. 8A, the first projection 115 having the same structure as that of the second embodiment shown in FIG. 5A is employed. However, the combination of the first projection 115 and the second projection 117 is not limited to the illustrated combination. The first projection 115 of any one of the above embodiments can be employed with the second projection 117.

Sixth Embodiment

A sixth embodiment will be described with reference to FIG. 9. In this embodiment, the inlet pipe 111 is formed at a position adjacent to one of the longitudinal ends of the upper tank 110. In the example of FIG. 9, the inlet pipe 111 is formed adjacent to the right end of the upper tank 110.

Also in this embodiment, the first projection 115 is formed on the inner wall of the upper tank 110 at the position where the cooling water flowing from the inlet pipe 111 hits on. Also, the second projection 117 is formed on the lower inner wall of the downstream end of the inlet pipe 111.

Specifically, the height of the second projection 117 gradually increases from the upstream end of the inlet pipe 111 toward the downstream end of the inlet pipe 111, similar to the example illustrated in FIG. 8A. Moreover, as the inlet pipe 111 is formed at the right end of the upper tank 110, the second projection 117 is sloped toward the left end of the upper tank 110 so as to direct the flow of the cooling water toward the left end of the upper tank 110.

Although not illustrated, the first projection 115 is formed such that the end 115 a is offset from the axis of the inlet pipe 111 to the right side such that the cooling water is easily introduced toward the left end of the upper tank 110.

In a case that the inlet pipe 111 is formed at the left end of the upper tank 110, the second projection 117 is sloped toward the right end, and the end 115 a of the first projection 115 is offset from the axis of the inlet pipe 111 toward the left end such that the cooling water is easily introduced toward the right end of the upper tank 110. Namely, the first projection 115 and the second projection 117 are configured such that the cooling water is more easily introduced toward a desired direction.

Accordingly, since the flow of the cooling water in the upper tank 110 is facilitated by the first projection 115 and the second projection 117, the flow speed distribution of the cooling water in the core 130 is reduced. As such, the flow of the cooling water improves in the radiator 100.

Other Embodiments

In the above first to fifth embodiments, the inlet pipe 111 is formed at the substantially middle position of the upper tank 110, and the first projection 115 is formed such that the end 115 a is aligned with the axis of the inlet pipe 111. However, it is not always necessary that the inlet pipe 111 is formed at the substantially middle position. The inlet pipe 11 can be formed at any position with respect to the longitudinal direction of the upper tank 110. In such a case, the end 115 a can be offset relative to the axis of the inlet pipe 111 according to the position of the inlet pipe 111 in the longitudinal direction of the upper tank 110. Namely, the end 115 a can be offset according to a ratio of a distance between the inlet pipe 111 and one of the of the upper tank 110 to a distance between the inlet pipe 111 and the other end of the upper tank 110.

Further, in a case that the axis of the inlet pipe 111 is not perpendicular to the longitudinal direction of the upper tank 110, i.e., inclined relative to the longitudinal direction of the upper tank 110, an angle of the inclination of sides/side walls 115 b of the first projection 115 and/or the second projection 117 can be varied appropriately such that the cooling water is smoothly introduced throughout the upper tank 110.

In the above embodiments, the inlet pipe 111 is integrally formed with the resinous tank 110. However, it is not always necessary that the inlet pipe 111 is integrally formed with the resinous tank 110. The inlet pipe 111 can be separately formed and coupled to the upper tank 110. Also, the upper tank 110 may be formed of a material such as aluminum, other than the resin. Namely, the present invention can be employed to a heat exchanger in which an inlet pipe is brazed to an aluminum tank. Further, the structure of the heat exchanger is not limited to the illustrated structure.

In the heat exchanger in which the height of the upper tank 110 is smaller than a diameter of the inlet pipe 111 as shown in FIG. 1, the flow speed distribution of the cooling water in the upper tank 110 will be easily generated. By employing the first projection 115 discussed in the above to such the heat exchanger, the cooling water is smoothly introduced in the upper tank 110 and the flow speed distribution of the cooling water in the upper tank 110 is effectively reduced.

Further, use of the present invention is not limited to the radiator 100. The present invention can be employed to other heat exchangers such as an intercooler, an oil cooler, an EGR gas cooler, and the like. Thus, the fluid is not limited to the engine cooling water.

Also, the above embodiments can be employed with any combinations. Furthermore, the first projection 115, inclined portion 116 and the curved wall may be formed in the lower tank 120 and the outlet pipe 121, if necessary, to smoothly discharges the fluid from the lower tank 120.

The present invention is not limited to the embodiments discussed in the above and illustrated in the drawings, but may be implemented in other ways without departing from the spirit of the invention. 

1. A heat exchanger comprising: a tank defining a tank space; a core having a plurality of tubes stacked in a longitudinal direction of the tank and in communication with the tank space; an inlet port disposed to the tank for introducing a fluid into the tank space; and a first projection disposed on an inner wall of the tank at a position where the fluid flowing from the inlet port hits on and configured to change a flow direction of the fluid in the longitudinal direction of the tank.
 2. The heat exchanger according to claim 1, wherein the first projection projects from the inner wall of the tank toward the inlet port in a form of substantially wedge.
 3. The heat exchanger according to claim 2, wherein the first projection includes an end and side walls extending from the end and connecting to the inner wall of the tank, and the side walls are inclined relative to the longitudinal direction of the tank.
 4. The heat exchanger according to claim 1, wherein the first projection projects from the inner wall of the tank toward the inlet port and has a substantially triangular shape.
 5. The heat exchanger according to claim 4, wherein the first projection includes an end and first and second side walls sloped away from the end.
 6. The heat exchanger according to claim 4, wherein the first projection has a third side wall on a side opposite to the end and extending in the longitudinal direction of the tank, and the third side wall is disposed downstream of the end with respect to the flow of the fluid.
 7. The heat exchanger according to claim 6, wherein the first projection includes a longitudinal portion extending along the third side wall in the longitudinal direction of the tank.
 8. The heat exchanger according to claim 1, further comprising a second projection disposed in the inlet port for guiding the flow of the fluid before hitting on the inner wall of the tank.
 9. The heat exchanger according to claim 8, wherein the second projection is configured to direct the fluid toward the first projection.
 10. The heat exchanger according to claim 1, wherein the inlet port has a diameter greater than a dimension of the tank in a direction perpendicular to the longitudinal direction.
 11. The heat exchanger according to claim 1, wherein the inlet port is defined by a pipe member integrally formed with the tank, and the pipe member defines an axis substantially perpendicular to the longitudinal direction of the tank.
 12. The heat exchanger according to claim 11, wherein the pipe member has an inclined portion at its downstream end connecting to the tank, and the inclined portion is inclined toward the first projection for directing the fluid toward the first projection.
 13. The heat exchanger according to claim 11, wherein a downstream end of the inlet pipe connects to the tank through a curved portion and the first projection is partly formed in the curved portion.
 14. The heat exchanger according to claim 1, wherein the first projection has an end, and the end is offset from a center of the inlet port in accordance with a position of the inlet port relative to the longitudinal direction of the tank.
 15. The heat exchanger according to claim 1, wherein the core includes a core plate to which ends of the tubes are connected, and the core plate is fixed to the tank such that the tubes are in communication with the tank space. 